Now a paper published this week in the journal Environmental Science and Technology by Nathaniel Warner formerly of Duke University and colleagues focuses on another of those environmental costs: disposal of wastewater.

Hydraulic fracturing, as the term implies, involves water — both at the front end with fracking fluid, the water-based chemical cocktail that is injected into the shale, and at the back end where there is flowback water and produced water.

Flowback water (which literally “flows back” during the fracking process) is a mixture of fracking fluid and formation water (i.e., water rich in brine from the targeted shale gas-rich rock). Once the chemistry of the water coming out of the well resembles the rock formation rather than the fracking fluid, it is known as produced water and can continue to flow as long as a well is in operation. (For more, see “Natural Gas, Hydrofracking and Safety: The Three Faces of Fracking Water.”)

As a general rule, you would not want to take a shower much less drink flowback or formation water, nor would you want to just pour the stuff into a river or stream (although that has been known to happen, as described here and here). Fracking wastewater can contain massive amounts of brine (salts), toxic metals, and radioactivity. And so the gas companies have a problem: what to do with the stuff.

One disposal route is injection into deep wells, and a good deal of flowback and produced water from the Marcellus Shale is transported to Ohio for just such a deep burial. But this method has its own problems — the injection process has the inconvenient habit of causing an earthquake every now and again.

Another alternative is waste treatment: removing the contaminants and then dumping the“clean” water into a nearby sewer or river. But you can’t use a standard municipal water treatment plant to treat flowback and produced water as those facilities are just not designed to handle the level of contamination, especially radioactivity, found in these waters. (See here, here, here, here and here.)

Left: contaminated water in. Center: sludge. Right: cleaner water out. Operators at an oil and gas wastewater treatment plant I visited last year claim the cleaned water on the right is suitable for dumping into the municipal waste water stream.

So how well do these facilities really do? What is their downstream impact? Warner and his colleagues set out to find out.

The Effluent From a Plant Designed to Treat Fracking Effluent

Specifically, the authors looked at the effluent from the Josephine Brine Treatment Facility in western Pennsylvania and its impact on downstream water quality and sediment. The plant, which only treats oil and gas wastewater, dumps its effluent into Blacklick Creek, a kayaking and whitewater destination. Over a two-year period beginning in August 2010, Warner et al. collected effluent as well as downstream and background water and sediment samples, and analyzed them for key contaminants and radioactivity.

You could say that the results raise some concerns:

While radioactive “radium [was] substantially (>90%) reduced in the treated effluents,” stream sediments at the point of discharge were about 200 times background levels. The good news is that most of the radium appears to be localized in those nearby sediments**. The concern is that by hanging around at elevated concentrations, it can potentially be a long-term source of radiation for nearby aquatic life. It also has the potential to be remobilized and transported downstream eventually.

Chloride and bromide concentrations downstream of the plant were on average 4.5 and 12 times background levels. The plant was found to contribute about 90 percent of the downstream chloride content. Bromide enrichment can be a problem for downstream drinking water treatment facilities given that carcinogenic compounds form during chlorination in the presence of bromide.

Effluent isn’t the only byproduct. As part of the treatment, chemicals are added to the fracking wastewater to precipitate out salts and metals. And just like the water from the plant, plant operators must have a place to send the precipitates to. Warner et al. calculate that each kilogram of the resulting sludge could contain roughly 900 becquerels of radium* (at 900 becquerels of radioactivity, 900 atoms of radium decay every second emitting a high-energy alpha particle and leaving behind a radioactive gas, radon). This level of radiation exceeds the level for application to soil and may also exceed some landfill limits as well. And if it exceeds landfill limits, then it has to be treated as a hazardous waste, which is another can of radioactive and contaminated worms in its own right.

Are all treatment plants like Josephine? I suspect not. One advanced plant I visited during an eco-fact-finding trip to Pennsylvania in June 2012, run by Eureka Resources, appeared to do a pretty thorough job of getting contaminants out of wastewater from fracking operations (see photo), but even it has garnered some air quality violations from EPA. And plants like Eureka’s are not a panacea: even these plants have to deal with the sludge that’s left behind, they are expensive, and at least for now, their current capacity is quite limited.

You gotta feel bad for the gas companies. Their shale gas boom keeps coming up with cracks they need to seal up — in this case the crack is leaking some really foul water.

_________________

End Note

* Assumes half of the wastewater treated at the facility is wastewater from Marcellus Shale gas wells.

2 Comments

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Trevor H

Oct 9, 2013

Bill – I’ve commented on a number of your posts and often maintained that the risks of the fracking operation itself are dwarfed by the risks of transportation and handling of the chemicals and waste at the surface and this post seems to confirm that.

I don’t think the gas companies need any sympathy, though, just consistent enforcement of high standards of environmental responsibility. If all the players are forced to shoulder the costs of proper waste handling then none need complain – the additional cost is simply passed on in the price of the product to the consumer. Feel sorry for the responsible companies that do a good job, which I think is the vast majority of the industry, because it’s the unethical operators that take shortcuts which both spoil the reputation of the industry and take additional profits.

One thing I thought was missing from your analysis, though, was a reference to safe levels of the contaminants found in the Blacklick. Radium at 200 times background definitively identifies the plant as a source, but what’s our safe threshold? 5 times? 1000 times? It would be useful to know that context to understand how worrisome this incident is.

That minor point aside, thanks for continuing to hold the industry accountable for minimizing its impact on the environment. We need people such as you who write in a fair and objective manner about how we can improve. I’ve worked in oil and gas exploration my entire career and I want to see us be as responsible as possible.

The authors write: “[Radium 226] 226Ra levels in stream sediments (544–8759 [Becquerel/kilogram] Bq/kg) at the point of discharge were ~200 times greater than upstream and background sediments (22–44 Bq/kg).”

The EPA has set the maximum level at 5 picocuries per liter of the combined value of Ra 226 and Ra 228 for drinking water, but that’s not really the right metric here because these are levels in sediments.

If these sediments were to be disposed of, a proxy for safety could be the levels that require disposal management: those range from 185 to 1850 Bq/kg (5 to 50 pCi/gram). The range of Ra 228 in sediments at the outfall ranged from 164 to 2187 Bq/kg. Thus, the combined concentrations of Ra 226 and Ra 228 exceed the range requiring management by as much as 60 times.

If the sediments were included in a cleanup covered under the Resources Conservation and Recovery Act (RCRA), the safe level would be much closer to the upstream background levels.